Simultaneous occurrence of an antiferroquadrupolar and a ferromagnetic transitions in rare-earth palladium bronze CePd₃S₄

Neutron powder diffraction experiments have been performed on CePd ₃S₄ as well as measurements of magnetic and transport properties on a single-crystalline sample. Magnetic susceptibility increases markedly below T_C = 6.3 K and a spontaneous magnetization appears below T_C. The logarithmic temperature dependence of electrical resistivity implies that CePd₃S₄ is classified into a Kondolattice compound whose Kondo temperature is comparable to T_C. Magnetic susceptibility is analyzed satisfactorily with a crystalline electric field model that the 4f ground state of Ce³⁺ is the Γ₈ quartet with the excited Γ₇ doublet located at 630 K. The magnetic structure of CePd₃S₄ was determined to be a canted structure with a canting angle of 51°. Such a canted structure is a result of the ferromagnetic (FM) ordering and simultaneous [100]-type antiferroquadrupolar (AFQ) ordering at T_C. The smaller magnetization values and an unexpectedly high T_C can be explained by the simultaneous occurrence of AFQ and FM order.